It is known to tow an airplane by means of a vehicle from its parking position in order to cause it to taxi over a portion of its path to a takeoff runway. However airports charge airlines for the use of such a vehicle. Proposals have been for an airplane to taxi under its own power by fitting one or more of its undercarriages with electric motors. However that can require the onboard electricity network and the auxiliary power unit to be overdimensioned. That is why, while the airplane is reversing from its parking position, provision is made to start one of the jets of the airplane. Once the jet is running, the onboard electricity network is also powered by the electricity generator associated with the jet. It can therefore deliver the power required for taxiing to the motorized undercarriage. Nevertheless, that mode of operation is not optimized.